Process of and apparatus for producing solid carbon dioxide



Wan/4 Jan. 10, 1933. E. G. SULLIVAN 1,893,852

PRocEss oF AND APPARATUS FOR PRoDUoING soLID CARBON DloxIDE Filed Feb. 17, 1951 2 sheets-sheet A TTORNEY.

Jan. 1 0, 1933.

E. G. SULLIVAN 1,893,852

PROCESS OF AND APPARATUS FOR PRODUCING SOLID CARBON DIOXIDE Filed Feb. 17, 1931 2 Sheets-Sheet 2 .mm r

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Patented Jan. 10, 1933 UNITED STATES PATENT ori-ICE EDWARD G. SULLIVAN, I' AMARILLO, TEXAS, ASSIGNOB TO JOSEPH S. BELT, 0F

' AIABILLO, TEXAS PROCESS 0F AND APPARATUS FOB PBODUING SOLID CARBON' DIOXIDE Application med February 17,*1931. Serial No. 516,491.

This invention relates to a process of and apparatus for producing solid carbon dioxide from iiue gases occasioned by burning natural gas with air and composed of about 10% carbon dioxide gas and about 90% nitrogen. shown in the pending application of Joseph S. Belt and Hamilton P. Cady, Ser. No. 424,655 filed January 30, 1930, it has heretofore been proposed to highly compress and cool ue gases and then expand them into a snow or converting chamber having external supercooling or refrigerating means, whereby a comparatively large percentage of the carbon dioxide gas contained in the iue gases is converted to solid or snow form The present invention differs from the prior apparatus and method referred to above in that the flue gases are compressed to a moderate pressure after being dried and moderately cooled, and nitrogen highly com'- pressed and cooled to a state of partial liquefaction is discharged together with these fiue gases and expanded within a snow cr converting chamber in conflicting jets so that the ue ases and. nitrogen are thoroughly mixed to utilize the cold temperature of the nitrogen in facilitating transition of the carb-on dioxide gas in the flue gases directly to a solid or snow, the snoW fallmg to the bottom of the converting chamber for being readily collected and pressed into cake form for commercial Y use.

A speciiic object of the present invention is to provide an improved process and apparatus of the character indicated above wherein provision is made for utilizing the residual nitrogen in the iiue gases after being expanded into the converting chamber for assisting in cooling and partially liquefying -the nitrogen prior to its expansion into the converting chamber.

Other objects and features of the invention will be apparent from the following description when considered in connection With the accompanying drawings, in which:

Figure 1 is a somewhat diagrammatic elevation of an apparatus suitable for carrying out the process of the present invention.

Figure 2 is an enlarged vertical longitudi- "0 nal section of the boiler furnace for generating the flue gases and forming part of the apparatus shown in Figure 1; and

Flgure 3 is an enlarged horizontal section of the converting chamber.

Referring in detail to the drawings, 5 in- 55 dicates a furnace which has a burner 6 supplied with natural gas from a suitable source, and also supplied with sufficient air to furnlsh the necessary oxygen for substantially complete combustion of the hydrocarbon constituents of the natural gas. A pipe 7 conducts the ue gases from the furnace 5 through a scrubber and cooler 8, in Which acids and odors are removed from the iue gases, and in which the Water vapor of the hot iiue gases is condensed. rlilhe gases pass .from the scrubber and cooler 8 through a pipe 9 to a conventional multiple stage compressor 10 having the usual intercoolers and after cooler, and in which some moisture is expressed from the gases and drawn oi as necessary in any Well known or preferred manner. The compressed and cooled gases arethen conducted by a pipe 11 to a preliminary cooler -C- Where they are reduced somewhat in temperature. From the cooler -C, the gases are conducted by a pipe 12 into a dehydrator 13 by' means of which any Water remaining in the gases is removed, and. by means of which such gases s are` effectively dried. As shown, this dehydrator may include a settling tank 14 in which the Water is removed from the gases, and a battery of absorbent dryers 15 through which the gases are conducted from the settling chamber 1e for having' any remaining moisture edectively extracted therefrom. Water collecting in the. chamber 14C and dryers 15 drains into a manifold 16 from which it may flow to any suitable point of discharge or disposal.

The compressor 10 places the lue gases under a pressure of 294C pounds per square inch, and after the flue gases are dried, they g5 are passed through successive coolers or refrigerators 17 for being cooled to a temperature of substantially -7 6 Fahrenheit. The Hue gases pass from the final coolers or refrigerators 17 by way of pipe 18, discharging 100 gen under a pressure of approximately 2940 pounds per square inch and at a temperature of about 251 Fahrenheit. As the nitrogen discharges into the convertin chamber 19 from the nozzle 22, it emerges 1n a jet transversely of the chamber 19 so that the jets of flue gases and nitrogen conflict and effect thorough mixture of the nitrogen and flue gases. As the cold nitrogen expands; to a pressure of 294 pounds per square inch, which is maintained within the converting chamber 19, it exerts a freezing influence upon the carbon dioxide gas contained in the flue ases, so that nearly 100% of the carbon ioxide gas is converted to a solid or snow which falls to the bottom of the converting chamber into a press -P- for being pressed or compacted and subsequently cut into cake or block form for commercial use. The converting chamber 19 has a top screened outlet chamber 23 from which leads a pipe 24 having ay control valve 25, and by means of which the remaining nitrogen, consisting of the nitrogen introduced as such and the residual flue gases, are allowed to escape from the converting chamber at a pressure of slightly less than 294 pounds per square inch and at a temperature of about 251 Fahrenheit.

Of the exhaust nitrogen from the converting chamber 19, a portion equal to the residual nitrogen from the Hue gases, less system leakage, is expanded through anl adiabatic engine 26 to one atmosphere pressure, whereupon it passes to a heat exchanger for finally cooling the high pressure nitrogen immediately prior to its expansion into the converting chamber 19. This heat exchanger is, as shown, preferably of the countercurrent type as generally illustrated at 27. In passing through the heat exchanger 27 this portion of the nitrogen is heated from 321 Fahrenheit to 251 Fahrenheit, and cools the high pressure nitrogen to about the latter temperature before passing through the pipe 21 into the converting chamber. The low pressure nitrogen then passes through a further heat exchanger 28 for cooling the high pressure nitrogen to about 225 Fahrenheit before the latter passes to the pipe 29, the low pressure nitrogen being thereby heated to 35 Fahrenheit before passing into the pipe 30. The low pressure nitrogen then passes from pipe 30 to still another heat exchanger 31 where it is heated to about 45 Fahrenheit and then exhausts through pipe 32 to the atmosphere. In the heat exchanger 31, the low pressure nitrogen cools a portion of the high pressure nitrogen from 62 Fahrenheit to Lacasse 22 Fahrenheit, the high pressure nitrogen being supplied to this heat exchanger by pipe 33 and passingV therefrom by way of pige 34.

he exhaust nitrogen from the converting chamber 19 which is not passed through the engine 26 is conducted by pipe 35 through heat exchangers 36 and 37 at a pressure of 294 pounds per square inch. When leaving the heat exchanger 37, the low pressure nitrogen passes to pipe 38 at a temperature of about 45 Fahrenheit. After passing through the heat exchangers 37 and 36, the high pressure nitro en passes to pipe 39 at a temperature of' a ut 225 Fahrenheit, and the pipes 29 and 39 connect together for passing through the heat exchanger 27 to the pipe 21. The low pressure or exhaust nitrogen passes from pipe 38 to a compressor 40 where its pressure is raised from 294 pounds per square inch to about 2940 pounds per square inch. This compressor 40 is pre erabl of the two stage type having an intercoo er and an after cooler, and the compressed nitrogen leaves the aftercooler of this compressor at about 80 Fahrenheit, whereupon it is conducted by pipe 41 to a water cooler 42 and an ammonia cooler 43 for being cooled to about 62 Fahrenheit. The high ressure nitrogen then passes partly to the eat exchanger 37 b way of pipe 44 and partly to the heat exclianger 31 by way of pipe 33. In assing through the heat exchangers 31 andp 37, the nitrogen is cooled to about 22 Fahrenheit, after which it passes by way of pipes 34 and 45 to a common ammonia cooler for being cooled to about 37 Fahrenheit. The nitrogen then passes from the ammonia cooler 46 to the heat exchangers 28 and 36 by way of pipes 47 and 48 for being cooled to the temperature of 225 Fahrenheit before passing to the final heat exchanger 27, as hereinbefore mentioned.

In operation, the partially liquefied nitrogen is expanded through nozzle 22 into the converting chamber 19 from a pressure of 2940 pounds per square inch to 294 pounds per square inch and at a temperature of 251 Fahrenheit. As this jet of cold expanding nitrogen strikes the jet of cooled dried and compressed flue gases issuing from the nozzle 20, the carbon dioxide gas in the iue gases is brought to a. suiiiciently low temperature to cause solidification of substantially all of the same. The pressure maintained within the converting chamber 19 by suitable means including valve 25 is just slightly lower than 294 pounds per square inch so that the flue gases may be discharged into the converting chamber at this pressure. By means of the ap aratus described a continuous supply of ighly compressed and cooled nitrogen is had together with a continuous supply of flue gases, the residual nitrogen of the fiue'gases being effectively llO utilized in cooling and partially liquefying the nitrogen used in the converting operation. Additional nitrogen may be supplied to the system as required from time to time in an suitable or preferred way, preferably a jacent the inlet of compressor 40 as indicated at 49.

In the operation of a plant of the present character, it will be necessary to burn considerably more gas than can be used in the process, in order to generate sucient steam as required for power purposes. The furnace 5 is accordingl provided with a dome 50 for receivin the iliiie gases and from which leads the pipe and also a stack or chimney 51 that opens to the atmosphere. This stac 51 has a suitable dam r 52 by means of which the desired portion of the flue gases may be diverted through the pipe 7 for use in the process.

In producing the snow or solid carbon dioxide within the convertin chamber 19, considerable of the snow wil stick or adhere to the inner surface of the converting chamber. In order to free this snow from the surface as it forms thereon, I provide within the converting chamber a U-shaped scraper 53 formed to contact the top Aand side walls of the converting chamber and carried at the top by an operating shaft 54 having an operating pulley ln this way the scraper 53 may be operated by power to continuously scrape the snow from the Walls ci the converting chamber as it adheres thereto or forms thereon. This snow will fall to the bottom of the converting chamber into the press -P- along with such snow as does not adhere to the inner surface of the converting chamber.

ln order that the nozzles 20 and 22 may not interfere with the rotation of the scraper 53, they are preferably located within suitable recesses 56 provided in opposed portions of the side Walls of the converting chamber 19 so that the nozzles 20 and 22 may terminate entirely outside the inner face of the side walls of the converting chamber.

F rom the 'foregoing description, it is believed that the present process and apparatus will he clearly understood by those y skilled in the art, as Well as its objects and features appreciated. While l have specified certain details of construction and exact temperatures and pressures which are deemed most practical, it is understood that minor changes-may he made or practiced with regard to details of the process Without departing from the spirit and scope of the invention as claimed.

What l claim as nevv is.:

1. rlhe process of making carbon dioxide snow which includes discharging moderately compressed and cooled dried due gases containing carbon dioxide gas into a converting chamber, and precipitating the carbon dioxide in the form of snow from the ue gases b subjecting the latter to the cooling action oa jet of expanding hi hly cooled nitrogen.

2. The process of ma 'ng carbon dioxide snow which includes discharging moderately compressed and cooled dried flue gases con` taining carbon dioxide gas into a converting chamber, and precipitating the carbon dioxide in the form of snow from the Hue gases by subjecting the latter to the cooling action o a jet of expanding highly cooled nitrogen, and maintainin a pressure in the converting chamber sli ht flue gases uring the precipitating operation.

3. The process of making carbon dioxide snow which consists in discharging dried ilue gases containing carbon dioxide gas into a converting chamber at a pressure of approximately 294 pounds per square inch and at a temperature of approximately 76 Fahrenheit, and precipitating the carbon dioxide from the ilue ases in the form of snow by subjecting the ue gases to the cooling action of partially liquefied nitrogen expanding from a pressure of approximately 2940 pounds at a. temperature of approximately 251 Fahrenheit.

4. The rocess of making carbon dioxide snow whic consists in. discharging dried flue gases containing carbon dioxide gas -into a converting chamber at a pressure of approximately 294 pounds per square inch and at a temperature of approximately -7 6 Fahrenheit, and recipitating the carbon dioxide from the ue gases in the forni of snow by subjecting the flue gases to the cooling action of partially liquefied ,nitrogen ex anding roina pressure of approximate y 2940 pounds at a temperature of approximately -251 Fahrenheit, and utilizing the residual nitrogen in the iiue gases in the partial lique- 'faction of the nitrogen used in the precipitating operation and as a component part or the nitrogen so used.

5. The process of making carbon dioxide snow which includes discharging moderately cooled and compressed dried iiue gases containing carbon dioxide gas and highly coinpressed and cooled nitrogen in coniiicting jets within a converting chamber, and permitting material expansion of thel nitrogen as it is discharged, whereby the cooling action of the expanding nitrogen on the lue gases causes precipitation of the carbon dioxide rom the Hue gases in the form orn snow.

6. in an apparatus for making carbon dioxide snow, a converting chamber, means for continuously supplying said converting chamber with moderately compressed and cooled dried lilue gases containing carbon dioxide gas means for supplying highly compressed and cooled nitrogen to the converting chamber in an expanding jet which condicts with the incoming flue gases to mix y below the pressure of the 'y therewith, means for conducting the nitrogen from the converting chamber and for utilizing the same in cooling the nitrogen prior to its discharge into the converting chamber.

7. In an apparatus for making carbon dioxide snow, means for partially liquefying nitrogen, a converting chamber, means for discharging the partially liquefied nitrogen into the converting chamber so as to expand within the later, means for supplying the converting chamber with dried moderately cooled and compressed flue gases containing carbon dioxide gas so as to mix with the incoming expanding nitrogen for utilizing the cooling action of the latter and precipitating the carbon dioxide in the flue gases to snow form, means to conduct the expanded nitrogen from the converting chamber, means for utilizing a portion of the escaping nitrogen in an amount approximating the residual nitrogen in the flue gases for power purposes and for cooling action upon the nitrogen suplied to the converting chamber, and means or returning the remaining nitrogen to be again partially liquefied and expanded into vthe converting chamber.

8. In an apparatus for making carbon dioxide snow, a converting chamber, means for supplying the converting chamber with conlicting jets of expanding partially liquefied f nitrogen and dried moderately com ressed and cooled flue gases containing car on dioxide gas, and means to remove snow from the walls of the converting chamber.

In testimony whereof I aix m signature.

EDWARD G. S LIVAN. 

